1. Field of the Invention
The present invention relates to an absorption air conditioner which can be suitably structured into an air-cooled structure.
2. Description of the Prior Art
In, for example, Japanese Patent Laid-Open No. 59-83717 low temperature water passes through a heat transfer pipe group disposed in an evaporator and is cooled by latent heat generated due to the evaporation of a refrigerant falling onto the heat transfer pipe group so that the cooling performance is obtained. In the heating mode, vapor of a high temperature refrigerant, generated in a high-temperature regenerator, is introduced into a medium-temperature heat exchanger to be condensed. As a result, medium-temperature water passing through the heat transfer pipe group is heated so that the heating performance is obtained.
In order to constitute an air-cooled absorption refrigerating cycle which is capable of performing the cooling operation at a density at which crystallization and solidification do not take place and at a pressure below the atmospheric pressure it is necessary for the density of an absorbent for a solution at the outlet port of the air-cooled absorber to be a low density which is substantially the same as that for the water-cooled apparatus. Accordingly, a structure has been employed which is arranged in such a manner that the air-cooled absorber is composed of a plurality of absorption units. Furthermore, the heat exchange with cooling air has been performed in such a manner that an absorption unit, disposed adjacent to a solution outlet port formed in the air-cooled absorber and in which the temperature and the density are low, is cooled by air of a relatively low temperature which is present adjacent to the inlet port. Furthermore, cooling air of a relatively high temperature, present adjacent to the outlet port, is used to cool the absorption unit which contains a relatively high temperature and high density solution to be introduced into the air-cooled absorber. As described above, the air-cooled absorber composed of a plurality of the units is employed to constitute a multipass perpendicular counterflow heat exchange cycle so that the heat exchange between cooling air and the absorption liquid are brought to an ideal state for the counterflow heat exchange. As a result, the temperature efficiency is improved so that an air-cooled double effect absorption refrigerating cycle of a water-lithium boromide system is realized. In the water-cooled system in which cooling water is, as an alternative to air, used to serve as the cooling medium for cooling the condenser and the absorber, the structure is similarly arranged such that the solution, in which the density of the absorbent is the thinnest in the cycle, is generated in the absorber.
Since the above-described conventional technology has been arranged in such a manner that the absorption liquid in which the density of the absorbent is the thinnest is generated in the absorber, the pressure of which is the lowest in the cycle, the pressure balanced temperature of absorption liquid is too low. As a result, the difference in the heat exchange temperature from the cooling medium is unsatisfactorily small. Therefore, the absorber must have an excessively large heat transfer area.
In order to reduce the size of the absorber, an absorption air conditioner has been realized in which the mass flow of the cooling medium is enlarged and thereby the temperature of the cooling medium at the outlet port is lowered so as to enlarge the heat transfer temperature difference from absorption liquid. However, excessively large energy for transferring the cooling medium, that is, an excessively large electricity input, has been required for each of the air cooling fan and the cooling water circulation pump.
Furthermore, the conventional cooling cycle cannot recover heat from a waste heat source the temperature of which is lower than the temperature level of the low-temperature regenerator.
In a case where an energy saving cycle is desired in which the quantity of the solution to be circulated can be reduced by enlarging the degree of condensation (density width) in the high-temperature regenerator or the low-temperature regenerator, the thick solution approaches the crystallization line at the largest density width because absorption liquid in which the density of the absorbent is the thinnest is generated in the absorber the pressure which is the lowest in the cycle. Therefore, crystallization can easily be taken place or the temperature level at which the high-temperature regenerator can be operated is raised excessively. As a result, there is a fear of the corrosion and the deterioration.
Another structure has been disclosed in, for example, Japanese Patent Laid-Open No. 62-202972 which is suitable to improve the temperature efficiency in the heat transfer process between cooling air and absorption liquid. However, the above-described structure has no means to enlarge the difference in the heat transfer temperature. Therefore, there arises a problem in that the air-cooled absorber must have an excessively large heat transfer area.